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Abstract:

In a method for operating a starter of a vehicle, a position of a starter
pinion is detected, and an advance of the starter pinion is regulated as
a function of the detected position. For example, the advance during the
meshing of the starter pinion with a starter ring gear of a drive motor
of the vehicle is regulated

Claims:

1. A method for operating a starter of a motor vehicle, comprising:
detecting a position of a starter pinion; and regulating an advance of
the starter pinion as a function of the detected position.

2. The method as recited in claim 1, wherein a speed of the starter
pinion is detected, and the advance of the starter pinion is regulated as
a function of the detected speed.

3. The method as recited in claim 1, wherein the detection of the
position of the starter pinion includes detection of an induction change
in response to the advance of the starter pinion.

4. The method as recited in claim 3, wherein the advance during the
meshing of the starter pinion with a starter ring gear of a drive motor
of the vehicle is regulated.

5. The method as recited in claim 4, wherein the starter pinion is
rotated during the meshing, in order to feel into a space between two
teeth of the starter ring gear.

6. The method as recited in claim 5, wherein the starter pinion is
rotated pulse-by-pulse.

7. The method as recited in claim 5, wherein upon detecting a contact of
a starter pinion tooth with a tooth of the starter ring gear, the starter
pinion is moved in a direction counter to the direction of the advance,
in order to create a distance between the starter pinion tooth and the
tooth of the starter ring gear.

8. The method as recited in claim 7, wherein after the distance has been
created, the starter pinion is rotated and moved in the direction of the
starter ring gear in order to mesh with the starter ring gear.

9. A device for operating a starter of a vehicle, comprising: a sensor
configured to detect a position of a starter pinion; and an advance
control configured to regulate an advance of the starter pinion as a
function of the detected position.

10. The device as recited in claim 9, wherein a coil assemblage is
provided in order to build up a magnetic flux for an inductive advance of
the starter pinion.

11. The device as recited in claim 10, wherein the sensor has a sensor
coil disposed in the coil assemblage for detecting an induction change in
response to the advance of the starter pinion.

12. The device as recited in claim 10, wherein the coil assemblage has a
sliding bushing for the displacement of an armature coupled to the
starter pinion.

13. The device as recited in claim 12, wherein the sliding bushing has at
least one magnetizable ring for influencing the magnetic flux.

14. The device as recited in claim 13, wherein the at least one
magnetizable ring is disposed one of displaceably or fixedly in the
sliding bushing.

15. The device as recited in claim 10, wherein a spring is provided to
retain the starter pinion in a position of rest, the spring being
disposed in a drive shaft of the starter.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method and device for operating
a starter of a motor vehicle.

[0003] 2. Description of the Related Art

[0004] As a rule, familiar pinion-based starter systems are designed in
such a way that they follow a sequence control. Intermediate states, such
as the striking of a tooth of a starter pinion on a tooth of a starter
ring gear during meshing of the starter pinion with the starter ring
gear, are bridged via spring travels, so that an electric relay contact
in a solenoid-operated switch of the starter is able to be closed, even
though the pinion is not yet engaged with a ring gear, i.e., the starter
ring gear of an engine flywheel. An electric motor of the starter system
already starts up in this state, and the gear wheels mesh due to the
rotary motion.

[0005] Because of its mechanical impacts on the teeth and at the limit
stop, this process is prone to bring about wear and causes noise
emissions. Especially in the case of vehicles having a start/stop
function, this leads to negative comfort characteristics of the vehicle
when starting the engine. Furthermore, the starter system must be
constructed more sturdily in order to ensure cycle life with respect to
starting, especially for vehicles having a start/stop function. This
leads to increased costs and considerable manufacturing expenditure.

BRIEF SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a method and a
device which overcome the known disadvantages, and which exhibit reduced
noise emission when starting the vehicle.

[0007] According to one aspect, a method is provided for operating a
starter of a vehicle. A position of a starter pinion is detected, and an
advance of the starter pinion is regulated as a function of the detected
position.

[0008] According to a further aspect, a device is provided for operating a
starter of a vehicle. The device has a sensor for detecting a position of
a starter pinion. The device also has an advance control for regulating
an advance of the starter pinion as a function of the detected position.

[0009] Thus, the position of the starter pinion is detected, especially
relative to a starter ring gear. An advance of the starter pinion in the
direction of the starter ring gear may be controlled to the extent that a
hard collision of the teeth of the respective gears is avoided. Thus, a
low-noise meshing is advantageously attained. Possible impacts may be
recognized and/or reduced. Preferably, the advance is regulated via power
electronics, in particular, a force built up by the advance is regulated.

[0010] According to one specific embodiment, a speed of the starter pinion
is detected, the advance of the starter pinion being regulated as a
function of the detected speed. For instance, a constant advance speed
may be set. In particular, a time characteristic of the speed may be
ascertained. Preferably, the time characteristic of the speed is
integrated, so that the position of the starter pinion may be calculated
based on the integral of the speed.

[0011] According to another specific embodiment, the ascertainment of the
position of the starter pinion includes ascertainment of an induction
change in response to the advance of the starter pinion. Measuring a
change in induction offers the special advantage that it may be carried
out in particularly sensitive fashion--for example, filtering to the
measuring signal is easily possible from the standpoint of circuit
engineering--and that the corresponding measuring signal may be made
available to a control algorithm for calculating an advance speed.

[0012] In another specific embodiment, the advance during the engagement
of the starter pinion with the starter ring gear of a drive motor of the
vehicle is regulated. In particular, the control during a meshing process
offers the advantage that possible impacts may be recognized in this
critical phase, and to that extent, may be avoided or reduced.

[0013] According to a further specific embodiment, the starter pinion is
rotated during the meshing, in order to feel into a space between two
teeth of the starter ring gear. Preferably, the starter pinion is rotated
pulse-by-pulse. The teeth of the starter pinion thus feel into the
corresponding spaces of the starter ring gear. This process of feeling
into the spaces advantageously reduces a mechanical impact of the gear
wheels. In particular, in so doing, a starter motor which is coupled to
the starter pinion is rotated, especially, is rotated slowly. Preferably,
the starter motor is driven accordingly by power electronics.

[0014] According to one specific embodiment, shortly before the starter
pinion reaches a limit stop, thus, shortly before the starter pinion is
meshed with the starter ring gear, the advance of the starter pinion is
reduced, so that advantageously, the limit stop is not reached with full
force.

[0015] In another specific embodiment, upon detecting contact of a starter
pinion tooth with a tooth of the starter ring gear, the starter pinion is
moved in a direction counter to that of the advance, in order to create a
distance between the starter pinion tooth and the tooth of the starter
ring gear. Instead of the starter pinion being moved further forward
against resistance, it is moved back somewhat, thus advantageously
avoiding damage to the starter pinion. For example, after the distance
has been created, the starter pinion is rotated and moved in the
direction of the starter ring gear, in order to mesh with the starter
ring gear. Thus, a new meshing attempt is carried out, this time, in
comparison to the previous meshing attempt, the starter pinion being
rotated, so that there is a possibility that in this meshing attempt, the
starter pinion tooth may be moved into a tooth space in the starter ring
gear. In particular, this process may be repeated until the starter
pinion has meshed with the starter ring gear.

[0016] According to one specific embodiment, the device has a coil
assemblage or coil pack in order to build up a magnetic flux for an
inductive advance of the starter pinion. An inductive advance offers the
special advantage that mechanical friction is reduced during the advance,
which means a corresponding wear is decreased. The coil assemblage
preferably includes two coils, which may also be denoted as primary coil
and secondary coil. Both the primary coil and the secondary coil may also
be denoted as actuator coils.

[0017] According to a further specific embodiment, the sensor has a sensor
coil, disposed in the coil assemblage, for detecting an induction change
in response to the advance of the starter pinion. Preferably, the sensor
coil is integrated into the primary coil and/or into the secondary coil.
In particular, the primary coil and/or the secondary coil is/are also
formed as a sensor coil. Particularly when ascertaining the induction
change, an induced voltage is measured that results especially from the
movement of the starter pinion and from a change in current in the coil
assemblage. The measured induced voltage is preferably filtered out of
the movement and made available to a control algorithm as a sensor signal
for the speed of the starter pinion. Thus, in advantageous manner, a coil
current may be set, especially with the aid of power electronics, in such
a way that a constant or regulated rate of advance of the starter pinion
is achieved. In another specific embodiment, the sensor coil may also be
formed separately from the primary coil and the secondary coil, thus, the
two actuator coils. The sensor coil is preferably formed separately from
the coil assemblage. That means, in particular, that the sensor coil is
not used as actuator coil, and so far as that goes, is also not actively
energized in these cases. Nevertheless, in a further specific embodiment,
in spite of the formation of the sensor coil separate from the actuator
coils or the coil assemblage, the sensor coil may also be used as a
further actuator coil, and particularly in this case, is actively
energized, that is, receives an electrical current.

[0018] In another specific embodiment, the coil assemblage has a sliding
bushing for the displacement of an armature coupled to the starter
pinion. The sliding bushing preferably has at least one magnetizable ring
to influence the magnetic flux. Thus, especially in an advantageous
manner, the controlled system behavior is linearized in terms of the
advance. Preferably, a plurality of rings is provided. The ring or rings
is/are preferably made of steel. In particular, the at least one
magnetizable ring is disposed displaceably or fixedly in the sliding
bushing. Preferably, a few rings may be disposed displaceably, and a few
further rings may be disposed fixedly in the sliding bushing. According
to a further specific embodiment, the rings have an identical or
different diameter. The ring is preferably formed integrally with the
sliding bushing. That is to say, the ring is a part of the sliding
bushing. According to another specific embodiment, the ring is formed as
a projection in the sliding bushing, across which the armature moves
during the axial movement along the sliding bushing. In particular, a
sliding bushing may also generally be denoted as a linear friction
bearing.

[0019] In a further specific embodiment, a spring is provided to retain
the starter pinion in a position of rest, the spring being disposed in a
drive shaft of the starter. Preferably, the spring may also be situated
in the area of the coil assemblage. In particular, the spring is disposed
at the starter pinion. In this manner, the spring may advantageously be
supported directly on the armature.

[0020] Hereinafter, a meshing mechanism denotes a mechanism which brings
about a meshing of the starter pinion with the starter ring gear. To that
extent, the device of the present invention may also be denoted in
particular as a meshing mechanism.

[0021] The meshing mechanism is preferably disposed concentrically around
the starter pinion, and in this context, preferably the mounting
dimensions of starters, especially of known starters, in the vehicle are
taken into account. An easy retrofit of known starter systems is thereby
permitted in advantageous fashion. In addition, the need for the
switching relay, disposed as a "piggyback," together with all
transmission elements such as splitter, meshing spring and its
suspensions, is advantageously eliminated. The meshing mechanism, i.e.,
the device may advantageously be integrated in the starter without
requiring more space. In particular, the movement of the armature on the
meshing magnet may be influenced by the insertion of magnetizable rings,
so that different movement profiles result, and in conjunction with the
closed-loop control, the meshing process may advantageously be influenced
even further.

[0022] The essence of the invention includes, in particular, the
electronic control and the interaction of the rotary and translatory
movement of a starter system, especially of the starter pinion. The one
active principle of the present invention--that according to one specific
embodiment, a change of an induced voltage in a sensor coil is measured
in order to determine a speed and or a position--may also be applied
generally to externally mounted mechanisms, externally pertaining
especially relative to the starter.

[0041]FIG. 17 shows an enlarged section of the force characteristic from
FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Hereinafter, identical reference numerals are used for identical
features.

[0043]FIG. 1 shows a device 101 for operating a starter (not shown) of a
vehicle. Device 101 includes a sensor 103. Sensor 103 is furnished to
detect a position of a starter pinion (not shown). Device 101 also
includes an advance control 105, which is furnished to regulate an
advance of the starter pinion, the control being carried out as a
function of the detected position of the starter pinion.

[0044] FIG. 2 shows a flowchart of a method for operating a starter of a
vehicle. In a first step 201, a position of a starter pinion is detected.
In a step 203, an advance of the starter pinion is regulated as a
function of the detected position.

[0045]FIG. 3a shows a starter 301 having a starter pinion 303 in a
non-engaged position. That is to say, starter pinion 303 is not meshed
with a starter ring gear (not shown). FIG. 3b shows starter 301 from FIG.
3a, starter pinion 303 being in an engaged position. That is, starter
pinion 303 is meshed with the starter ring gear (not shown).

[0046] Starter 301 has an electric motor 305 which has carbon brushes 307
and brushes 309 as current collectors. Electric motor 305 also has a
field frame 311. In addition, electric motor 305 includes a rotor 313
having windings. Magnets 315 are formed around rotor 313. A support 319
for an electric-motor shaft 321 is formed in an axis of symmetry 317 of
electric motor 305. Electric-motor shaft 321 is coupled to a planetary
gear 323, that is coupled to an overrunning clutch 325. In particular,
overrunning clutch 325 may be in the form of a roller-type overrunning
clutch.

[0047] A drive shaft 326 of starter pinion 303 is supported by a friction
bearing 327, that is retained by an end shield 329. An intermediate
bearing 331 is also formed between overrunning clutch 325 and friction
bearing 327. Drive shaft 326 preferably has a splining.

[0048] Power electronics, which are represented symbolically by a
transistor 335, are mounted in an add-on area 333.

[0049] FIG. 4 shows an enlarged view of starter pinion 303.

[0050] Starter pinion 303 is moved inductively by a coil assemblage having
a primary coil 401 and a secondary coil 403. In so doing, the power
electronics energize primary coil 401 and secondary coil 403, a magnetic
flux thereby being built up. This magnetic flux gives rise to a
mechanical force on an armature 405. Armature 405 is coupled mechanically
to starter pinion 303, so that starter pinion 303 is able to move forward
and backward along axis of symmetry 317 in accordance with the magnetic
flux. Due to this movement, the induction in the magnetic circuit
changes, an induced voltage thereby resulting on secondary coil 403. In
this respect, secondary coil 403 may also be denoted as a sensor coil.
This induced voltage results in particular from the movement, and from
the change in current in the two coils 401 and 403. The induced voltage
of the movement is filtered out and made available to a control algorithm
as a sensor signal for the speed of starter pinion 303. Thus, especially
with the aid of the power electronics, a coil current is able to be
adjusted or regulated in such a way that a constant or regulated advance
speed of starter pinion 303 is obtained. The position of starter pinion
303 may be inferred, as well, preferably based on the integral of the
speed. In this manner, possible mechanical impacts may advantageously be
recognized and/or reduced. In one specific embodiment not shown, only
primary coil 401 is actively energized, that is, receives an electrical
current. Secondary coil 403 is thus not used as an actuator coil, and so
far as that goes, is not actively energized. An induced voltage,
resulting because of the translatory movement of armature 405, on
secondary coil 403, which may also be denoted here as a sensor coil, is
measured in analogous fashion, so that with the aid of suitable
filtering, the speed and the position of armature 405 may be ascertained.
When examples having an active energizing of primary coil 401 and of
secondary coil 403 are described hereinafter, the intention is for the
case with only active energizing of primary coil 401 to always be
included, as well. In these cases, secondary coil 403 is not used as an
actuator coil, and to that extent, is not actively energized.

[0051] The coil assemblage also includes an outer sleeve 407 and a
forced-in sleeve disk 409, each of which may preferably be made of
magnetizable steel. In this respect, outer sleeve 407 may also be denoted
as a magnetic casing. So far as that goes, sleeve disk 409 may also be
denoted as a magnetic disk. Sleeve disk 409 and outer sleeve 407 form one
sleeve in which sensor coil, i.e., secondary coil 403, and primary coil
401 are disposed on a winding support 411. Winding support 411 may also
be denoted as a coil form.

[0052] Moreover, at the inner diameter of primary coil 401, a sliding
bushing 413 is integrated, in which armature 405 is able to slide during
its axial movement. Preferably, sliding bushing 413 may also be disposed
in such a way that armature 405 is guided at the inside diameter.

[0053] To linearize the controlled system behavior as well as to influence
the magnetic flux lines, which may be effected especially by the
insertion of magnetizable steel rings 415 into sliding bushing 413,
preferably a function may be represented dependent on the advance
direction of starter pinion 303, so that the control algorithm of the
power electronics may be carried out more easily, i.e., also in
controlled fashion, for the standard cases of meshing. In particular,
steel rings 415 may be part of sliding bushing 413 and/or be formed as
projections which are passed over during the axial movement of armature
405. Moreover, rings 415 may preferably be disposed immovably and/or also
in part movably. That is, movably disposed rings 415 also move along
during an axial movement of armature 405. In an exemplary embodiment not
shown, rings 415 may have a larger, a smaller or perhaps the same
diameter in relation to an armature diameter. Preferably all rings 415
have the same diameter. In particular, rings 415 may have different
diameters.

[0054] Furthermore, a spring 417 is formed which, via an engaging piece
419, is able to retain starter pinion 303 in a defined position of rest
when starter 301 is inactive or after the starting procedure. Spring 417
is disposed in drive shaft 326 of starter 301. An open shaft end, which
is facing away from the advance direction, is closed with a screw plug
(not shown), which means the retention force may be set in advantageous
manner. The other spring end is supported via engaging piece 419, which
transfers the spring force to starter pinion 303. To that end, drive
shaft 326 is open radially owing to a slit (not shown) in the working
area, to advantageously ensure a transfer of force and/or an adjusting
path.

[0055] In particular, given adequate spatial conditions, spring 417 may
also be disposed in the area of coils 401 and 403 or preferably on
starter pinion 303, and thus also preferably be supported directly on the
armature. In this case, in particular, an axial retaining device is
implemented accordingly at armature 405, and especially at starter pinion
303, to advantageously permit reliable absorption of the axial forces and
accelerations occurring.

[0056] In particular, starter pinion 303 and drive shaft 326 have a spur
toothing (not shown), since the rotary movements during meshing are
realized by electric motor 305 of starter 301. By preference, the
toothing may be implemented as splining, especially in widely varying
types of construction, which permits a cost-effective possibility for the
transfer of torque.

[0057] Preferably, starter pinion 303 is connected by an armature disk 419
to armature 405, which initiates the axial movement of starter pinion
303. Armature disk 419 is preferably made of a non-magnetizable material,
so that a magnetic shunt via starter pinion 303 is advantageously
avoided. For example, armature disk 419 may be made of metal or from one
or more non-metals. Preferably, it is made to be strong and
wear-resistant, enabling it to handle radial movements.

[0058] Armature disk 419 is forced at its outside diameter into armature
405 up to a predetermined end stop, and for the purpose of withstanding
excessive axial stress, is safeguarded from slipping out by a circlip
(not shown). At its inside diameter, armature disk 419 is supported on
starter pinion 303 via a sliding disk 421. A circlip (not shown) is
disposed here as well for the purpose of preventing loss, so that an
unintentional decoupling of starter pinion 303 is advantageously avoided.
Preferably, these axial retaining devices may also be implemented
differently, but for reasons of space, should be as compact as possible.

[0059] The decoupling of the rotary motion of starter pinion 303 with
respect to fixed armature 405 takes place preferably at the inside
diameter, owing to sliding disk 421, and is therefore formed in
especially low-wear fashion as an assembly.

[0060] Preferably, armature 405 is guided with the aid of a feather key
(not shown) at the outside diameter, which in turn is preferably secured
in intermediate bearing 331. For example, the anti-rotation element may
also be implemented in another form using alignment pins and/or other
standard elements and/or perhaps by design-engineering forms of armature
405 and/or intermediate bearing 331 and/or the coil housing.

[0061] Overrunning clutch 325, which, by preference, is implemented as
meshing element on the standard generator or electric motor 305, is
preferably axially non-moving, thus fixed, and is preferably part of the
reduction gear or planetary gear 323, and in particular, is integrated in
it. In particular, overrunning clutch 325 accommodates the axles of the
planetary wheels (not shown) of planetary gear 323 and is integrated, for
example, as an element of the planetary-gear carrier (not shown) in
intermediate bearing 331. Intermediate bearing 331 also produces a
support for rotor 313 of electric motor 305 and drive shaft 321 in the
middle of starter 301.

[0062]FIG. 5 shows an axial view of starter pinion 303, engaging piece
419 and drive shaft 326 in the area of the toothing.

[0063]FIG. 6 shows an electrical circuit plan of starter 301 from FIGS.
3a and 3b. A controller 601 regulates a coil current of primary coil 401
and of secondary coil, i.e., sensor coil 403, respectively, in each case,
an amplifier 603 being connected between coils 401 and 403. A resistor
605 is inserted upstream of primary coil 401 for the purpose of limiting
current. In addition, a diode 607 is inserted in the coil circuit of
primary coil 401. The inductances of coils 401 and 403 are marked L1 and
L2, respectively. Preferably, L1 and L2 are identical. For instance, L1
may also be greater than L2 and vice versa.

[0064] The controller has an interface 609 to electric motor 305, which
may also be denoted as a starter motor. The elements having reference
numerals 611 identify ground connections of the electrical starter
system. The element having reference numeral 613 identifies a capacitor.
A switch 615 opens or closes an electrical connection to a steady plus
617 of a starter battery (not shown). A starter signal to start electric
motor 305 is supplied to controller 601 via a terminal 619.

[0065] The two coils 401 and 403 are energized with the aid of controller
601, a magnetic flux thereby building up which attracts armature 405
magnetically in the direction of the two coils 401 and 403. In this
respect, armature 405 may also be denoted as a magnet armature. By
preference, armature 405 is made of iron. Translatory motion v of
armature 405 is identified by the arrow having reference numeral 619.
This translatory motion v of the armature into the coil assemblage formed
by the two coils 401 and 403 generates an induced voltage in coil 403,
which is filtered out and made available to the control algorithm of
controller 601. An advance of armature 405 is regulated as a function of
the measured induced voltage, in particular by regulating a respective
coil current accordingly.

[0066]FIG. 7 shows a further view of the electrical circuit plan from
FIG. 6. The controller is in the form of power electronics 701, and
includes a meshing control 703 that, in particular, regulates a meshing
current 705. Power electronics 701 further include a starter control 707
that, in particular, regulates a starter current 709. Power electronics
701 also include a meshing regulator 711, a starter regulator 713, a
position detection 715, a phase detection 717, an operating system 719, a
monitoring/diagnostic unit 721 and a sensor algorithm 723. Since, in
particular, controller 601 is able to regulate an advance of starter
pinion 303, controller 601 may also be denoted as an advance control.

[0067] The element having reference numeral 725 is a starter battery which
is connected with its positive pole via switch 615 to controller 601.
Starter battery 725 is connected to an electrical system (not shown) of
the vehicle via a current line 727.

[0068] The element having reference numeral 729 identifies a starter ring
gear that, in particular, includes a gear wheel disposed on a flywheel of
an internal combustion engine (not shown). For the sake of clarity, not
all reference numerals for the individual elements of starter 301 are
marked in in FIG. 7.

[0069]FIG. 8 and FIG. 9, respectively, show a time characteristic of the
meshing current and of the starter current. Current | is plotted in amps
against time t in arbitrary units.

[0070]FIG. 10a and FIG. 10b show a further starter 1001, which is
constructed similarly to starter 301. FIG. 10a shows starter 1001 with
non-engaged starter pinion 303. FIG. 10b shows starter 1001 with engaged
starter pinion 303. For the sake of clarity, the starter ring gear is not
shown.

[0071] FIG. 11 shows an enlarged view of starter pinion 303 from FIGS. 10a
and 10b. Power electronics, represented symbolically by transistor 335,
energize a coil pack or coil assemblage 1101, which, analogous to FIG. 4,
has a primary coil and a secondary coil (both not shown), a magnetic flux
thereby being formed which brings about a mechanical force on armature
1103. In particular, a coupling between armature 1103 and starter pinion
303 may be analogous to the specific embodiment shown in FIG. 4. Starter
pinion 303 is moved forwards, and due to the change in the magnetic
circuit, an induced voltage is obtained on the secondary coil resulting
from the movement and the change in current. The induced voltage of the
movement is filtered out and made available to the control algorithm as a
sensor signal for the speed of the meshing relay. Thus, the coil current
may be regulated via the power electronics in such a way that a constant
advance speed or regulated advance speed is obtained. Likewise, the
position of starter pinion 303 may be inferred based on the integral of
the speed, and possible mechanical impacts may advantageously be
decreased.

[0072] In order to linearize the controlled system behavior, an air gap
1105 is formed which represents a function depending on the advance
direction, so that advantageously, the control algorithm of the power
electronics may be executed more easily.

[0073] Furthermore, a spring 1107 is formed, which resets starter pinion
303 after the starting process and retains the meshing mechanism with
starter pinion 303 in a defined position of rest. In addition, an
engaging piece 1109 is formed, which is constructed analogously to
engaging piece 419, and produces the same technical effects.

[0074] Generally, a mechanical overrunning clutch 1111 may be formed both
in the moving part and in the static part of the meshing mechanism.

[0075]FIG. 12, FIG. 13 and FIG. 14, respectively, show a time
characteristic of the current in the primary coil, a time characteristic
of the induced voltage in the sensor coil and a time characteristic of
the filtered-out voltage of the movement. In FIG. 12, a current | is
plotted in amps A against a time t in milliseconds ms. In FIGS. 13 and
14, in each case a voltage U is plotted in volts against a time t in ms.
In all three figures, one can recognize a modulation in the curves
depicted which results especially because rotation pulses act upon the
starter pinion, that is, it is rotated pulse-by-pulse.

[0076] In the graph shown in FIG. 15, an air gap is plotted in meters m
against a travel characteristic in meters m. The travel characteristic
corresponds to the forward travel of the starter pinion. Thus, the air
gap represents a function depending on the advance direction, which
results in a linearization of the controlled system behavior. Reference
numeral 1501 denotes a curve without a geometrical change, thus, without
an air gap. The curve having reference numeral 1503 shows the
characteristic with a geometrical change, thus, with an air gap.

[0077]FIG. 16 shows a force characteristic of a solenoid that is formed,
in particular, by the primary coil and the secondary coil. The force
which is generated by the solenoid is plotted in newtons N against a
travel or travel characteristic in meters m.

[0079] With the aid of the present invention, the following functions, in
particular, are made possible in the overall assembly made up of the
starter and internal combustion engine.

Meshing into the Switched-Off Internal Combustion Engine

[0080] In the case of a stop function for start/stop vehicles, the starter
pinion may already be meshed into the switched-off internal combustion
engine, so that the starting time may be reduced by the period of time
for the meshing process. Especially for reasons of comfort, this process
is realized as quietly as possible and without great mechanical impacts.
To this end, the pinion moves, preferably slowly, toward a possible
tooth-on-tooth contact, while meantime, power electronics output rotation
pulses to the starter motor. A tooth-on-tooth contact may be detected
based on a speed signal of the meshing process, and the function of
feeling between the teeth may be activated. This is accomplished with a
combination of translatory and rotary movements of the starter pinion.
When this state is overcome, the end position is then approached with a
defined speed, and the holding current is reduced to a minimum. The
period of time of the holding phase is a function, in particular, of the
state of charge and a coil temperature. In any case, startability of the
internal combustion engine must be ensured. The holding current is
increased during the starting process, in order to ensure a reliable
state of the pinion position. After the starting process has been carried
out, the pinion is brought out of the toothing of the starter ring gear.
This is realized by interrupting the magnetic circuit as well as via a
return spring, especially spring 417, until the pinion is in the position
of rest.

Quick Start

[0081] In the case of the first start or when working with a damaged
battery, the meshing mechanism should only mesh as quickly as possible
and start the internal combustion engine in response to the start
command. To that end, the actuators, i.e., the primary and secondary
coils, are fully energized, and rotation pulses are applied to the
starter motor until the meshing mechanism has reached the end position.
The meshing current is now brought to a holding level, and the starter
motor is fully energized until the internal combustion engine has been
started successfully. As described above, after the starting process has
been carried out, the starter pinion is pushed out and brought into the
position of rest via a return spring.

Meshing into the Coasting-Down Internal Combustion Engine

[0082] At the beginning of the stop phase, the internal combustion engine
is switched off and coasts down due to its own inertia of mass. If there
is a drop below the refiring limit and the internal combustion engine is
to be started again as quickly as possible, it is necessary to mesh into
the coasting-down internal combustion engine, and the internal combustion
engine must be pulled along by the starter to rotational speed until it
is able to resume operation independently.

[0083] In this case, the starter motor is accelerated with limitation of
current and the meshing mechanism executes a feeling movement until the
pinion engages in the starter ring gear. The starter is now in the
overrunning phase, so that the starter current may now be increased, and
the starter motor brings the internal combustion engine to the refiring
speed again. As described, after the starting process has been carried
out, the starter pinion is pushed out and brought into the position of
rest via a return spring.

"Feeling" Function

[0084] The feeling function describes the interaction of the meshing
mechanism and the starter motor during the engaging of the gear wheels
upon meshing. In this context, the starter motor is driven in such a way
that it generates rotational pulses at the starter shaft. Meanwhile, the
meshing mechanism will effect a linear forward movement until there is
contact of the starter pinion with the ring gear on the flywheel of the
internal combustion engine. A tooth-on-tooth situation is detected, the
meshing mechanism makes a small backwards movement, the starter receives
a rotational pulse, and the meshing mechanism tries again to mesh using a
changed pinion angle. This is carried out until the pinion is meshed
without great expenditure of force.